1. Field of the Invention
The present invention relates to a clarification plant for treating water with a container which has a water inlet and a water outlet and whose inner space comprises a treatment area and a sedimentation area arranged thereunder.
2. Description of the Prior Art
Clarification plants of this type are used for purifying and treating water and waste water from industry and households.
It is crucial thereby that as complete a removal as possible of noxious substances takes place and that the water has a high oxygen content after treatment. The main purification is thereby achieved by means of biological degradation processes by micro-organisms which are specifically introduced to the waste water or are cultivated in the clearing basin.
In production plants there occur organically highly polluted waste waters which according to the respective statutes for indirect discharges must be pre-purified to a prescribed COD-limiting value. This purification must therefore also take place in constricted spatial conditions in the production plants.
For this purpose, conventional clarification plants are used in which the water to be treated is introduced into various basins one after the other. In a first basin there takes place a mechanical pre-clarification of the water which is then directed into a basin for aeration by oxygen. In this aeration tank, the water is aerated with pure oxygen or with air and hence the oxygen content of the water is increased. In this basin or also in an adjacent basin the biological purification stage is completed, in which, with the aid of micro-organisms, most of the noxious substances in the water to be treated are degraded. In this process, a great deal of oxygen is consumed by the micro-organisms with the result that a constant supply of oxygen must be maintained. In order to prevent agglomeration of the micro-organisms into larger biological structures and the settling of these micro-organisms on the base of the container, the waste water must be constantly agitated. Adjacent to the biological clearing basin there is a sedimentation area in which surplus suspended matter in the waste water, such as for example agglomerations of micro-organisms as sewage sludge, are deposited. This area of the clarification plant is designed as a still zone for the treated water. The water which is extracted from the sedimentation basin is extensively free of noxious substances and, after further enrichment with oxygen, can be released into the environment.
The described clarification plant has a very high spatial requirement since an individual basin is required for the individual functions of pre-clarification, biological purification and sedimentation and also oxygen enrichment of the clarified water.
A disadvantage furthermore in the reactors according to the state of the art is that a high input of air is necessary for adequate enrichment of the water to be purified with oxygen and that these reactors have a very high energy consumption for the air introduction and the circulation of the liquid to be purified.